Vertically adjustable table



March 30, 1954 G. A. DUS ENBURY VERTICALLY ADJUSTABLE TABLE' 2 Sheets-Sheet 1 Filed July 6 1951 INVENTOR @44 BY 44, r

ATTORNEY) March 30, 1954 DUSENBURY 2,673,773

VERTICALLY ADJUSTABLE TABLE Filed July 6, 1951 2 Sheets-Sheet 2 INVENTOR 4 MM .4 4 21% v M ATTORNEY Patented Mar. 30, q 1954 OFFICE VERTICALLY ADJUSTABLE TABLE George A. Dusenbury, Saluda, N. 6.

Application July 6, 1951, Serial No. 235,485

Claims. 1

The present invention relates to tables and particularly to tables provided with means which enables the user to vary at will the height of the table top or article holding platform above the supporting fioor.

I'he common household table has heretofore been constructed in many forms and it has been widely appreciated that a table the top or article supporting platform of which be adiusted vertically when desired is adapted to be used for a greater number of purposes than tables of nonadjustable type. While tables embodying means for effecting changes in height have long been available it is usually found that any table which embodies means whereby its top moves upwardly or downwardly is likewise increased in weight, bull: or cost over tables of the non adiustable type, or rendered objectionably insecure, the re sult being that few tables of the adjustable type have met with public favor. It is the purpose of the present invention to provide an adjustable table which is so simple in its construction that it is in weight, bulk and cost approximately the same as comparable tables of non adiustable character and, furthermore, is as secure and strong as though it were of a similarly constructed but non-adjustable type.

The improved table comprises essentially a top of normal appearance, preferably circular, and a support, also of normal or at least not unusual superficial appearance, comprising, for instance, three legs pivotally connected to a common hub the lower ends of which engage the ground or floor and the upper ends of which provide three spaced points of support for the table top. arrangement is such, however, that, by angularly rotating the table top about a vertical axis passing through its center, the upper ends of the several legs may be simultaneously moved toward the axis of rotation of the top or moved away from that axis, thus causing the several legs to simultaneously pivot about the block to which they are mutually connected intermediate their ends respectively. Thus, the arrangement is such that rotation of the table top in one direc tion about its vertical axis will effectuate movement of both the upper and lower ends of each table leg toward the vertical axis about which the top is angularly moved with the net result that the height of the support is increased. When the table top is rotated in the opposite direction about its vertical axis relatively to the support both the upper and lower ends of each of the table legs are permitted to reccdc from the vertical axis of the top so that the net result 2 is a shortening of the support, measured vertically, and a lowering of the table top.

The table is preferably provided with special means for guiding the upper ends of the table legs in their rocking movements, so that, by this simple act of relatively rotating the table top and support, the vertical adjustment of the top is brought about with certainty, and the table leg upper ends if desired, be actually attached to the table top by means which permits relative sliding of table top and such upper ends.

in the accompanying drawings one embodiment of th invention is illustrated by way of example.

In the drawings,

Figure l is a perspective view of the table on a relatively small scale;

Figure 2 is a side elevation, partly broken away, of one simplified embodiment of the invention, the table bein shown in two positions .tment by the use of full and dotted lines; 0 e 3 is a diagram provided to make clear the manner in which relative rotation of the top and support brings about change in positions of the upper ends of the legs and causes change in height of the support;

Figure 4 is a side elevation of a further form of table embodying the invention, partly broken away;

Figure 5 is a section on line 5-5 of Figure 4;

Figure 6 is a section on line 6-45 of Figure i;

Fi ure 7 is a short vertical section through edge of the table top showing one form of means for slidably connecting the upper end of a table leg to the table top;

Figure 8 a section through portion of the table top, taken along a substantially radial line, showing a modified form of means for connecting the upper end of a table leg to the table top; and

Figure 3 is a section on line 9-9 of Figure 8.

The top it of the table shown in Figures 4, 5, 6 and 7 is preferably circular but may be polygonal if desired, its shape having no important bearing upon the manner in which the table functions. Secured to the undersurface of the top are three curved retainers l2, each in the form of a slotted tube attached to the table top by any suitable means, the slot opening downwardly and inwardly as shown. Each curved retainer is sufficiently long to subtend an arc of approximately as indicated in the diagram Figure 3, in which the retainers are indicated by the curved lines its, it?) and lie, the periphcry of the table by the numeral We, and a point on the vertical axis about which the table rotates being indicated at l3. The three tubular retainers l2a, I21) and [2c are similarly curved and similarly constructed and arranged about the axis l3. Preferably they are spirally curved, although some deviation from mathematically true spirals is permissible. The upper ends of the legs of the support may be caused to occupy various positions along the associated retainers, as will hereinafter be made clear.

The support comprises three preferably straight legs i l each of which is mounted, at a point intermediate its ends and preferably slightly above its midpoint, upon a horizontal pivot IS, the three pivots 16 being disposed at angles of 120 with respect to each other and being embedded in a common hub or block [1 the faces of which make equal angles with each other, i. e. a horizontal section through the block is an isosceles triangle. Each leg is therefore pivoted at approximately its midpoint for rocking movement in a vertical plane about a horizontal axis, the plane being offset from the vertical axis about which the top is caused to revolve when the table height is to be adjusted, this axis being indicated by the chain line 58 in Figure 4.

The upper end of each leg is preferably rounded and is housed within the associated elongated curved retainer l2 in such manner that it may not escape but may nevertheless slide longitudinally when the support and table top are relatively moved. It will thus be clear that in the form of the invention shown in Figures 4 to 7 the table top and support are connected together in such manner as to permit them to be relatively rotated about axis I3, without disengaging one from the other until the upper ends of the slots emerge from the ends of the several slotted tubular containers. Such rotation causes the upper ends of the table legs to simultaneously move in the general direction of the axis l3 or simultaneously recede from the axis it, the movement of each table leg upper end not being truly radial with respect to the axis 53 but in a plane, such as the plane indicated by the chain line 20 in Figure 3, offset from axis l3, which plane, however, swings about the axis [3 as a center from the position in which it is shown in Figure 3 at 29, 20 to the position in which it is shown in that same figure and indicated by the numerals 2i, 2!. Relative movement of top and support may be halted at any desired point so as to bring the plane of swinging movement of each leg into position to intersect the curved line He at any intermediate point, such as point I), c, or d, which points are at different distances from the axis of rotation l3, an infinite adjustment of elevation of the top, within the limits of overall adjustment of the table, being thus possible.

It will be observed from an inspection of Figure 3 that, by reason of the fact that the plane within which each leg of the table moves is offset from the axis of relative rotation of the top and support, and because of the spiral curvature of the retainer, the angular relationship between the plane of leg movement and a tangent to the retainer at the point of intersection of this plane and curved line 12a is substantially constant. In other words, the pressure exerted by the upper end of each leg against the retainer I2, which is always outwardly directed, will be substantially normal to the retainer at the point of contact between leg and retainer. There will therefore be little tendency of the leg to slip along the retainer due to any weight, however great, which may be placed upon the table top. The nature of the relationship between the several table legs and the associated retainers is of importance, the adjustment means provided being thus of the self-locking type, and adjustment resulting only from deliberate action by the user of the table. The weight of the table top will, of course, substantially increase the degree of frictional engagement between the upper ends of the legs and the retainers and, to facilitate relative rotation of top and support, the user will preferably grasp the table top by its edges and lift slightly to relieve the frictional forces tending to retard table top rotation relatively to the support.

In order to laterally support and guide the upper ends of the several legs M in their movements a rotatable frame is provided. This frame is pivotally mounted upon the underside of the table top if, in such manner that it will rotate about the axis 513, and has three outwardly projecting arms 3i each provided with a slot 32 through which the upper ends of the table legs respectively project. The frame 30 rotates freely relatively to the top and hence, as th top is rotated relatively to the support, it will remain stationary and, as previously explained, function to support and guide the several table leg upper ends their inward or outward movements. In the form of the invention shown in Figure 7, the arms of this frame 3!] are in the nature of rods rather than slotted members and the upper end of each leg id is vertically slotted, as at Me, for the reception of the rod. The invention may be otherwise modified in its details of construction, without loss of function or result, as will be apparent.

In the simple embodiment of the invention shown in Figure 2 of the drawings the retainers comprise simple strips 58 secured to the undersurface of table it and the upper ends of the legs bear upwardly against the undersurface of the table and outwardly against the inner surface of the associated retainers respectively. Relative adjustment of the top and support is effected in the manner previously described. In all forms of the invention frictional engagement between the curved retainers l2 and the upper ends of the several legs should be sufficiently great to prevent accidental rotary motion of the table top, and lowering thereof, regardless of the load imposed thereon.

In lieu of the slotted tubular retainers such as retainers l2 described two spaced retainers t2 and 34 of substantially rectangular cross section may be employed, the enlarged rounded upper end Ma of each leg is fitting into the helical slot thus formed. A pin Mb passes through this rounded end and prevents escape of the end E la from the slot, except at the ends thereof, the ends of the pin resting upon the upper faces of the associated parallel members of arms 3!. The top and support are thus rotatably secured together, detachment of one from the other being effected by turning the top until the ends of the legs of the support have emerged from the ends of the slots and the legs have been manipulated until the pin it!) associated with each been brought into registry with the transverse slot 32a of arm 3!. By withdrawing pins Mb through apertures tie the legs may be entirely disengaged from the top.

Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is:

1. In an adjustable table, a top and a support therefor, said top and support being relatively rotatable about a common vertical axis, the sup port comprising a hub intersected by said vertical axis and a plurality of legs, means mounting said legs upon the hub for rocking movements, respectively, in angularly disposed vertical planes which are horizontally spaced from said vertical axis, and a plurality of elongated retainers secured to said top, each retainer being engaged at any one of a plurality of points by the upper end of one of said legs and constituting means limiting the outward movement thereof, said retainers being disposed in a circular series centered on said vertical axis, and each being continuously curved in such manner that the plane in which the associated leg rocks defines therewith, at each possible point of engagement oi": leg and retainer, approximately equal angles with a tangent to the retainer at that point so that the leg and retainer will not slip relatively to each other in the absence of a manually applied turning force, the upper ends of the several legs being slidable along the retainers which they respectively engage upon the application of a manual force which brings about relative rotation of top and support, and the legs thus caused to simultaneously rock upon their respective mountings to vary the effective height of the support, frictional engagement of the leg upper ends and the respective retainers preventing relative rotation of top and support in the absence of a manually applied turning force.

2. In an adjustable table, a top and a support therefor, said top and support being relatively rotatable about a common vertical axis, the support comprising a hub intersected by said vertical axis and a plurality of legs, means mounting said legs upon the hub for rocking movements, respectively, in angularly disposed vertical planes which are horizontally spaced from said vertical axis, and a plurality of elongated retainers secured to said top, each retainer being engaged at any one of a plurality of points by the upper end of one of said legs and constituting means limiting the outward movement thereof, said retainers being disposed in a circular series centered on said vertical axis, the upper ends of the several legs being slidable along the retainers which they respectively engage upon the application of a manual force which brings about relative rotation of top and support, and the legs thus caused to simultaneously rock upon their respective mountings to vary the effective height of the support,

frictional engagement of the leg upper ends and the respective retainers preventing relative rotation of the top and support in the absence of a manually applied turning force, and means for laterally supporting the upper end of each leg while freely permitting the rocking movement thereof.

3. The combination set forth in claim 2 in which said laterally supporting means comprising a frame secured to the table top for rotation about an axis, said frame having arms extending outwardly in a plane parallel to the table top and provided with leg engaging surfaces.

l. The combination set forth in claim 2 in which said laterally supporting means comprising a frame having slots through which the upper ends of the several legs, respectively, project, said frame being movably supported upon the table top.

5. In an adjustable table, a top and a support therefor, said top and support being relatively rotatable about a common vertical axis, the support comprising a hub intersected by said vertical axis and a plurality of legs, means mounting said legs upon the hub for rocking movements, respectively, in angularly disposed vertical planes which are horizontally spaced from said vertical axis, and a plurality of elongated retainers secured to said top, each retainer being a slotted tube, the upper ends of the respective legs being slidably housed therein, said retainers being disposed in a circular series centered on said vertical axis, the upper ends of the several legs being slidable along the retainers which they respectively engage upon the application of a manual force which brings about relative rotation of top and support, and the legs thus caused to simultaneously rock upon their respective mountings to vary the effective height of the support, frictional engagement of the leg upper ends and the respective retainers preventing relative rotation of the top and support in the absence of a manually applied turning force.

GEORGE A. DUSENBURY.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 509,005 Voeltzkow Nov. 21, 1893 583,013 Ebert May 18, 1897 1,495,991 Drynan June 3, 1924 2,582,791 Page Jan. 15, 1952 FOREIGN PATENTS Number Country Date 891,805 France Mar. 21, 1944 

